Shinji Kagawa admits life at Manchester United was "particularly difficult", but the playmaker says his heart was always at Borussia Dortmund.
The Japan international rejoined the Bundlesliga side on deadline day after two frustrating seasons at Old Trafford. His first year was the last of Sir Alex Ferguson's reign and his second was the first under new coach David Moyes, scoring six goals in 38 games during his time in England.
Now the 25-year-old is back at the Westfalenstadion and enjoying playing football again under Jurgen Klopp. According to Kagawa, he would only have left United for one club.
He told reporters: "My decision was clear, I wanted to return to Borussia Dortmund and only to Borussia Dortmund. I want to achieve success with this club again, and with no other. Only facts matter in football - stats, goals, assists, titles, and a lot was missing in this regard.
Kagawa added: "That was probably why they no longer included me in their plans. Everybody knows that my second year at Manchester United was particularly difficult. The manager did not really count on me, and the team was also on a bad run. That means I am all the more delighted to be back. My heart had remained at Borussia Dortmund anyway."
On Tuesday, Borussia Dortmund strikers Ciro Immobile and Pierre-Emerick Aubameyang scored either side of halftime to give their side a 2-0 with over Arsenal on Tuesday, kick-starting the German side's Champions League campaign in Group D.
Immobile, signed from Torino in the offseason, sprinted almost half the length of the pitch and held off Arsenal defender Laurent Koscielny before dispatching a low shot inside the far post just before the break.
''I'm very happy to score, that we won, because it hasn't been easy for me to settle into the Bundesliga. I'm happy that I was able to make my teammates happy,'' Immobile said.
Aubameyang scored three minutes into the second half after a brilliant chip over the defense from Kevin Grosskreutz, whose clearance led to Immobile's opener. Aubameyang stumbled initially, but recovered to take the ball past Arsenal `keeper Wojciech Szczesny and guide it past the flailing Mikel Arteta on the line.
Information from The Associated Press contributed to this report.
